Method of reducing corrosion and corrosion byproduct deposition in a crude unit

Abstract

A method of optimizing system parameters in a crude unit to reduce corrosion and corrosion byproduct deposition in the crude unit is disclosed and claimed. The method includes measuring or predicting properties associated with the system parameters and using an automated controller to analyze the properties to cause adjustments in the chemical program to optimize the system parameters. Adjusting the system parameters effectively controls corrosion in the crude unit by reducing the corrosiveness of a fluid in the process stream and/or by protecting the system from a potentially corrosive substance. System parameter sensing probes are arranged at one or more locations in the process stream to allow accurate monitoring of the system parameters in the crude unit.

The claimed invention is: 
     
       1. A method of reducing corrosion and/or corrosion byproduct deposition in a crude unit, the method comprising:
 (a) providing a process stream flowing through the crude unit, wherein a process stream portion comprises process stream water, wherein the process stream comprises a chloride ion concentration that comprises spikes that occur over time, and wherein the process stream water has a pH that varies over time; 
 (b) introducing influxes of a plurality of compositions into the process stream, wherein the plurality of compositions adjust a plurality of measured and/or predicted properties of the process stream water associated with crude unit corrosion and/or corrosion byproduct deposition, wherein the plurality of compositions includes a caustic composition that is injected into the process stream to control the chloride ion concentration and a neutralizing composition to control pH of the process stream water; 
 (c) automatically measuring and/or predicting the plurality of properties of the process stream water at one or more points in the crude unit, said properties including at least chloride ion concentration and pH of the process stream water, and wherein said measuring and/or predicting with respect to the chloride ion concentration occurs to provide frequent data that is available show the spikes in the chloride ion concentration over time; 
 (d) providing optimum ranges associated with the measured and/or predicted properties of the process stream water; and 
 (e) controlling the influxes of the plurality of compositions responsive to the measured and/or predicted properties of the process stream water in a manner effective to maintain the properties of the process stream water in the optimum ranges to thereby reduce crude unit corrosion and/or corrosion byproduct deposition, said controlling comprising the step of: if a measured and/or predicted property is outside of an optimum range associated with that property, causing a change in an influx of a composition into the process stream, the composition capable of adjusting the measured and/or predicted property in a manner to bring the measured and/or predicted property within said optimum range, and wherein controlling the influx of the caustic composition comprises using the frequent data of the chloride ion concentration occurs to smooth the variation associated with the spikes in the chloride ion concentration. 
 
     
     
       2. The method of  claim 1 , wherein step (c) comprises: (i) converting each measured property into an input electrical signal capable of being transmitted to a controller and (ii) transmitting the input electrical signal to the controller. 
     
     
       3. The method of  claim 2 , including transmitting the input electrical signals via a wireless interface. 
     
     
       4. The method of  claim 2 , wherein the controller is operable to: (i) receive the transmitted input electrical signals; (ii) convert the received electrical signals into corresponding input numerical values; (iii) analyze the input numerical values: (iv) generate corresponding output numerical values; (v) convert the output numerical values into corresponding output electrical signals; and (vi) transmit the output electrical signals. 
     
     
       5. The method of  claim 4 , including transmitting the output electrical signals via a wireless interface. 
     
     
       6. The method of  claim 4 , wherein the controller is operable to: (i) analyze the input numerical value, and (ii) determine if the input numerical values correspond to the corresponding optimum ranges associated with the measured properties. 
     
     
       7. The method of  claim 6 , wherein if a input numerical value does not correspond to the corresponding optimum range, the transmitted output electrical signal causing the change in the influx of the corresponding composition into the process stream, the composition capable of adjusting the measured and/or predicted property in a manner to cause the input numerical value to correspond to the optimum input range. 
     
     
       8. The method of  claim 1 , including continuously or intermittently measuring and/or predicting the measured and/or predicted properties. 
     
     
       9. The method of  claim 1 , including monitoring the measured and/or predicted properties in real time. 
     
     
       10. The method of  claim 1 , wherein the plurality of measured and/or predicted properties further includes a measured and/or predicted property that is selected from the group consisting of: iron ion concentration; non-iron metal ion concentration; corrosion rate; and combinations thereof. 
     
     
       11. The method of  claim 10 , wherein the crude unit has a plurality of components including an atmospheric tower with at least one heat exchanger, and wherein the pH and chloride ion concentration are derived from a dew point water sample and/or an accumulator boot water sample in the crude unit and the iron ion concentration or the non-iron metal ion concentration is derived from the accumulator boot water sample in the crude unit. 
     
     
       12. The method of  claim 11 , including obtaining the dew point water sample and/or the boot water sample with an online, optionally automated, sampling device. 
     
     
       13. The method of  claim 1 , wherein and optimum range is user-defined. 
     
     
       14. The method of  claim 1 , including operating the method continuously, automatically, online or on a batch basis. 
     
     
       15. The method of  claim 1 , including operating the method over a network. 
     
     
       16. The method of  claim 1 , wherein step (e) comprises a step of using a hierarchy logic to prioritize a measured or predicted property with respect to another measured or predicted property. 
     
     
       17. The method of  claim 1 , wherein step (c) further comprises the steps of measuring or predicting an Fe ion property of the process stream, and wherein step (e) further comprises using the measured or predicted Fe ion property to control an influx of a filming inhibitor composition. 
     
     
       18. The method of  claim 1 , wherein step (e) comprises using a controller to intermittently adjust the influxes of the plurality of compositions. 
     
     
       19. The method of  claim 1 , wherein step (e) comprises using a controller to continuously adjust the influxes of the plurality of compositions. 
     
     
       20. The method of  claim 1 , wherein step (e) comprises using a controller to intermittently adjust the influxes of the plurality of compositions according to a predetermined schedule. 
     
     
       21. The method of  claim 1 , wherein step (e) comprises controlling a pH property of the process stream using a measured difference of pH properties at two sample points in the process stream. 
     
     
       22. The method of  claim 1 , wherein step (e) comprises controlling a chloride ion property of the process stream using a measured difference of chloride ion properties at two sample points in the process stream. 
     
     
       23. The method of  claim 1 , wherein a composition of the plurality of compositions comprises a neutralizer and is used to adjust a pH property and comprises 3-methoxypropylamine, monoethanolamine, N,N-dimethylaminoethanol, or methoxyisopropylamine. 
     
     
       24. The method of  claim 1 , wherein a composition of the plurality of compositions comprises a caustic agent that is used to adjust a chloride ion property. 
     
     
       25. The method of  claim 24 , wherein the caustic agent comprises NaOH. 
     
     
       26. The method of  claim 1 , wherein a composition of the plurality of compositions comprises a filming inhibitor used to adjust an Fe ion property and comprises an oil soluble blend comprising an amide and an imidazoline.